Changes to the code, described by ABPI president Vincent Lawton as 'fundamental', will come into effect on 1 January (PRWeek, 18 November).

From next year, companies will only be able to offer delegates economy-class air travel to attend meetings, while lavish venues will be off-limits.

Promotional material will be more tightly monitored, and relations between drugs firms and patient groups must be more transparent. Red Door Communications managing director Catherine Warne said: 'All our clients already operate within the new code.'

Ketchum UK health managing director Avril Lee said: 'We already have one of the most regulated pharma industries in the world – it should be business as usual for those already working to these standards.'

But one unnamed PRO said: 'The biggest change will be how we work with third parties. Many top professors have expectations as to how they will travel – it will be quite hard to get them to travel economy class.' Another PRO told PRWeek: 'When does a setting for a conference become a luxury one that would contravene the code? These things are difficult to define.'

Medicom Group managing director Martin Ellis said: 'The rule on economy travel is well overdue – a small number of opinion leaders have for years demanded business-class travel while being among the first to criticise elements of the industry's conduct.'

Ozone director Andrew Knill said: 'The real parameters of the code will be defined by the first wrist slappings dished out to those who err. The first major promotions of 2006 will be done with hesitant steps.'

Ellis added: 'I don't believe the ABPI would have published revised guidelines if the industry had not been the largely unjust target of repeated attacks on its reputation.'